PREP: Preheat the oven to 375 degrees F. Generously grease a muffin tin with nonstick spray. Lightly dust with flour and set aside. (Don't use liners; these muffins stick!) If using coconut oil, melt it then measure to get 1/2 cup. Set it aside so it can come back to room temperature.
WET INGREDIENTS: Measure out pumpkin to get exactly 1 and 1/2 cups. Add to a large bowl (you'll have a few tablespoons pumpkin leftover -- the perfect amount for pumpkin protein shake or pumpkin overnight oats!).
WET INGREDIENTS CONT.: To the pumpkin, add in 3/4 cup white sugar, 3/4 cup brown sugar, and 1/2 cup melted coconut oil that has cooled back to room temperature. (We want it melted, but not hot). Mix with a wooden spoon until combined and emulsified. Add in eggs, one at a time, mixing well after each addition.
DRY INGREDIENTS: In a large bowl, whisk together 1-3/4 cups flour, 1 teaspoon baking soda, 3/4 teaspoon fine sea salt, 2 teaspoons cinnamon, 1/2 teaspoon pumpkin pie spice, 1/4 teaspoon nutmeg, 1/4 teaspoon allspice, 1/16 teaspoon cloves (if using), and any desired mix-ins (see Note 1). Stir until combined.
COMBINE: Add 1/2 of dry ingredients right on top of wet and stir, with a wooden spoon, until combined. Add remaining dry ingredients and stir until combined and there are no streaks of flour. Do not over mix. Divide the batter evenly among the 12 muffin tin cavities, using all the batter. (The muffin cavities will be very full!)
TOPPING: In a separate small bowl, whisk together the remaining 2 tablespoons tightly packed brown sugar and remaining 1/4 teaspoon pumpkin pie spice. Sprinkle this mixture evenly on the tops of the muffins.
BAKE: Bake for 23-28 minutes or until a toothpick comes out clean from the center muffin (25 mins is perfect in my oven!). Don't under-bake or these will be overly moist. Remove from the oven and let cool for 5 minutes in the pan before transferring to a wire cooling rack to allow them to finish cooling. These muffins are best at room temperature, so allow time for them to thoroughly cool.